To destroy a specific target of a defined armor protection and size, a given fragmentation warhead must deliver a large number of optimally sized fragments within an effective lethal area. To combat multiple threat scenarios, the U.S. military must maintain supplies of several different fragmentation warheads, each type adapted for use against a particular target set. This obligatory approach creates a burden on logistics and supply. Additionally, existing artillery and mortars produce limited lethality depending upon the grade of steel used in their shells. Making more lethal, multi-purpose munitions available to the military would result in significant inventory reductions and cost savings. This invention is a high performance variable lethality, multi-purpose warhead using a novel adaptive fragmentation mechanism. This technology will enable the modern war fighter to instantly modify a fragmentation warhead in the field generating a desired fragment size to neutralize a broad range of targets from personnel to light armored vehicles. Additionally, adaptive fragmentation will minimize collateral damage by focusing the warhead's lethal effects upon the intended targets. The U.S. military employs fragmentation warheads against a wide variety of targets ranging from personnel, radar systems, trucks, parked aircraft, and rocket launchers to armored personnel carriers and self-propelled artillery. One significant obstacle to mission success is that a fragmentation warhead designed to defeat personnel is not generally effective against materiel targets including trucks and light armored vehicles, where fragments of relatively greater size and mass are required. Military units must maintain supplies of several different fragmentation warheads, each type adapted for use against a particular type of target. This results in a burden on logistics and supply. Existing artillery and mortars produce limited lethality depending upon the grade of steel used in their shells. Warhead designers have tried several techniques to enhance fragmentation including using harder High Fragmentation (HF) steel in the shell body, scoring the shell body, and adding preformed fragments. While these techniques can improve lethality, each traditional approach presents its own problems. Manufacturing HF steel involves a time consuming and costly heat treatment process. Scoring the casing weakens the shell's structural rigidity presenting potential problems related to survivability. Specifically, the scored grooves act as stress concentration points during the set back stage of gun launch. Adding preformed fragments helps to assure that the warhead delivers a few optimally sized fragments but it fails to enhance the fragmentation of the existing shell casing. To effectively engage multiple target types, the U.S. military requires an easily producible, multi-mode warhead alternative at a reasonable cost. By fitting conventional fragmentation warheads with relatively inexpensive, dynamically configurable patterned inserts to control the fragment mass distribution lethality can be increased. This new insert addresses the downfalls of the existing fragmentation enhancement methods because the insert requires no modifications to the existing projectile body; manufacturers can mass produce the simple insert parts for low cost using casting, stamping, or rolling methods and inexpensive materials including steel, copper, and plastics; and the insert can tailor the fragmentation masses and distribution for the best possible performance. For artillery, this ensures optimal lethality against both trucks and personnel and not just the latter. The dynamically configurable controlled fragmentation insert is effectively a patterned sleeve that fits inside the shell casing. The sleeve contains the cylinder of explosive material. The sleeve pattern is made up of rings stacked one on top the other. The individual rings can move independently of one another and a unique pinning mechanism holds the parts in a selected configuration. The war fighter can realign the insert parts by manipulating the fuse assembly to create different geometric patterns, each designed to engage a different target set with optimally sized fragments. Creating the effects of multiple linear shaped charges, the individual geometric shapes that make up the insert pattern focus the explosive energy released upon detonation to generate multiple high-velocity jets of insert material that cut up the steel shell casing in predefined areas. To engage enemy troops, the war fighter can deploy the warhead without changing the default mechanical offset of the insert pattern to produce smaller, lighter fragments with relatively higher velocities. To defeat materiel targets, the war fighter can easily “dial in” the insert pattern offset through the fuse assembly to configure larger fragments with greater penetrating power. Now, the war fighter can instantaneously configure one warhead in the field to engage multiple target types. This insert technique has enhanced capability with respect to fragmenting thick-walled, high-strength steel shells and has the unique patterned stacked ring configuration. It functions by forming jets of material, much like a linear shape charge. The jets cut into the shell body breaking it into smaller pieces. The patterned ring orientation, frequency, and geometric profiles can be modified to produce different combinations of large and small sized fragments. The sleeve can be made out of a variety of materials. Generally, denser and more ductile materials will perform the best but lower cost materials such as steel, copper, and plastic work too. Adaptive fragmentation benefits the modern war fighter because warhead engineers may retrofit existing projectiles using the multi-mode controlled fragmentation insert without modifying the shells. This new technology will also serve the U.S. military far into the future on grenades through mortar and artillery rounds up to tactical missiles. Additionally, future warhead designs could easily incorporate a mechanism to alter the fragmentation insert pattern in flight to adapt to rapidly changing battlefield conditions. For example, the war fighter could deploy a warhead configured to neutralize enemy personnel using smaller fragments and then remotely change the warhead's insert pattern in flight to defeat vehicles with larger fragments as the enemy combatants seek cover. The variable lethality warhead enhances the U.S. military's capabilities by optimizing lethality, minimizing collateral damage, enabling the military to multitask munitions to engage expanded target sets, reducing the costly burden on supply and logistics, and in that new warhead development can use lower cost, commonly available steels.